Kin Wang To

Validation of a portable recording device (ApneaLink) for identifying patients with suspected obstructive sleep apnoea syndrome

Background: Polysomnography (PSG) is currently the standard diagnostic procedure for sleep apnoea. This study evaluates the diagnostic accuracy of a portable recording device, ApneaLink (AL; ResMed, Poway, CA, USA) for detection of sleep apnoea in comparisons against PSG.

Pharmacokinetics of Plasma Efavirenz and CYP2B6 Polymorphism in Southern Chinese

Cytochrome P450 2B6 (CYP2B6) is the main metabolizing pathway for efavirenz (EFV), the prescription of which is associated with neurologic side effects. The authors conducted a study on the prevalence of CYP2B6 polymorphism, profile of side effects, and pharmacokinetics of EFV in a group of human immunodeficiency virus (HIV)-infected southern Chinese. Patients with HIV were recruited at the Shenzhen City Third Peoples Hospital, China. The prevalence of CYP2B6 G516T and plasma EFV concentration were determined. Pharmacokinetics was assessed using blood samples of selected patients at time 0, 1, 2, 4, 8, 12, and 24 hours after the last dose of EFV. Between October 2007 and June 2008, 79 Chinese patients with HIV were recruited. Sequencing of CYP2B6 at position 516 gave 42 GG, 34 GT, and 3 TT genotypes, with corresponding mean spot plasma EFV level of 3.4, 4.1, and 8.1 mg/L, respectively. The allelic frequency of 516 G>T was 0.25. Univariate analysis showed that plasma EFV level correlated with genotype (P = 0.02). Eighteen patients completed the pharmacokinetic study: TT genotype gave the longest half-life (t1/2), highest plasma EFV concentration, and largest area under the curve. The volume of distribution per surface area (Vdss), total clearance (Cltot), and elimination rate constant (ke) were the lowest. There was no association between the occurrence of side effects and the EFV concentration (χ2 test, P > 0.05). The EFV pharmacokinetics of TT genotype differed significantly from GG and GT genotypes. Accumulation of EFV may potentially occur over time, causing toxicity in TT and GT genotypes.

Mesenteric fat thickness is associated with increased risk of obstructive sleep apnoea

Mesenteric fat is a type of intraperitoneal adipose tissue draining into portal circulation. The objective of this study was to investigate the relationships between mesenteric fat thickness and obstructive sleep apnoea (OSA) in patients with suspected OSA.

Increasing the coverage of influenza vaccination in healthcare workers: review of challenges and solutions.

Seasonal influenza vaccine uptake rate of healthcare workers (HCWs) varies widely from <5% to >90% worldwide. Perception of vaccine efficacy and side-effects are conventional factors affecting the uptake rates. These factors may operate on a personal and social level, impacting the attitudes and behaviours of HCWs. Vaccination rates were also under the influence of the occurrence of other non-seasonal influenza pandemics such as avian influenza. Different strategies have been implemented to improve vaccine uptake, with important ones including the enforcement of the local authoritys recommendations, promulgation of practice guidelines, and mandatory vaccination polices. Practised in some regions in North America, mandatory policies have led to higher vaccination rate, but are not problem-free. The effects of conventional educational programmes and campaigns are in general of modest impact only. Availability of convenient vaccination facilities, such as mobile vaccination cart, and role models of senior HCWs receiving vaccination are among some strategies which have been observed to improve vaccination uptake rate. A multi-faceted approach is thus necessary to persuade HCWs to participate in a vaccination programme, especially in areas with low uptake rate.

Mesenteric fat thickness is associated with metabolic syndrome independently of Apnoea–Hypopnoea Index in subjects with obstructive sleep apnoea

Mesenteric fat thickness (MFT) was associated with metabolic syndrome (MetS) and obstructive sleep apnoea (OSA) in separate studies. This study aimed to assess whether the association of MFT with MetS was independent of OSA in subjects with suspected OSA.

Sleep quality in efavirenz-treated Chinese HIV patients – comparing between GT and GG genotype of CYP2B6-516 G/T polymorphisms

Seventy-two adult Chinese HIV-positive treatment-naïve patients were recruited in a study to evaluate prospectively the associations between CYP2B6 516 G/T polymorphisms and sleep quality following treatment with an efavirenz-based regimen. Overall, the patients gave an allelic frequency of 0.3 for CYP2B6 516 T, and a genotype frequency of 9.4% for TT. Compared to GG, GT gave a higher median value of plasma efavirenz level at four weeks (3.77 mg/L vs 2.59 mg/L, p < 0.001) and 12 months (3.57 mg/L vs 2.97 mg/L, p = 0.026). Using generalised estimating equations analysis to track the variance over time, there was poorer Pittsburgh Sleep Quality Index in GT compared to GG, while GT was associated with a higher efavirenz level of >4 mg/L. There was however no difference in the component sleep scores nor was there direct association between sleep quality and plasma efavirenz levels. The results suggested that CYP2B6 genotype was associated with different patterns of sleep problems, further investigation of which is warranted with the objective of optimizing therapy with efavirenz-based regimens.

Pulmonary scedosporium infection as a complication of infliximab therapy for ankylosing spondylitis

A 47-year-old man with a negative Mantoux test received infliximab 800 mg fortnightly in August 2005 for treatment of ankylosing spondylitis. He developed haemoptysis after receiving the third dose in September 2005 and therefore infliximab was stopped. CT thorax …

Tumour necrosis factor antagonist and tuberculosis in patients with rheumatoid arthritis: an Asian perspective.

Rheumatoid arthritis (RA) is a systemic autoimmune disease in which inflammation of the joints is one of the dominant clinical abnormalities resulting in serious morbidity. Over the past decade, tumour necrosis factor (TNF) antagonist has revolutionized the treatment of RA. However, the subsequent increased risk of developing tuberculosis is one of the major drawbacks of this otherwise effective treatment. Latent tuberculosis infection (LTBI) is an asymptomatic form of tuberculosis that is confined by the hosts immune system. Active tuberculosis may develop when the immune status weakens. This risk is much higher in patients receiving TNF antagonist. Traditionally, tuberculin skin test (TST) is used to diagnose LTBI. Unfortunately, TST cannot distinguish bacillus Calmette‐Guérin (BCG) vaccination from tuberculosis making it difficult to use as a reliable diagnostic tool. In addition, possible anergy and interaction of the altered autoimmune status in rheumatological diseases further complicate the interpretation of TST results. Although interferon‐gamma release assay (IGRA) has improved the diagnosis of LTBI in immunocompetent individuals, its respective sensitivity/specificity values are unknown in patients with autoimmune disease due to variable pretest probability and lack of confirmatory test for LTBI. Thus, the use of IGRA for screening LTBI is variable among different countries. This review explores the prevalence of tuberculosis in patients receiving TNF antagonist in countries with different tuberculosis disease burdens and the potential mechanisms for variation in the incidence of tuberculosis with different TNF antagonists, the current practice guidelines for assessing the risk of LTBI in different countries, and the possible solutions for improving diagnosis, monitoring and management of LTBI.

Role of nasal positive end expiratory pressure valve as an alternative treatment for obstructive sleep apnoea in Chinese patients.

As compliance of continuous positive airway pressure (CPAP) for treatment of obstructive sleep apnoea (OSA) is often suboptimal, a less cumbersome treatment is desirable. We explored the clinical usefulness of nasal positive end expiratory pressure (nPEEP) valves.

Comparison of empirical continuous positive airway pressure (CPAP) treatment versus initial portable sleep monitoring followed by CPAP treatment for patients with suspected obstructive sleep apnoea

Background:  Polysomnography is labour‐intensive for diagnosing obstructive sleep apnoea (OSA). We compared two algorithms for initiating continuous positive airway pressure (CPAP) treatment for patients with suspected OSA.